Originally Posted by TheCheese
I'm busy right now, I can't spend time looking through matches at the moment. Federer and Nadal both do this.
Edit: Here you go. http://www.youtube.com/watch?v=sU14bDScU8E
I know what you're going to say. "That's just practice, he's not trying". Yes, that's true, but he also does this during a match if his footwork is off. I mean, obviously he's going to do that rather than force a straight arm and completely miss the ball.
You just posted a video of Roger Federer in your discussion about Rafael Nadal. I don't know if I've seen a greater fail.
While their method of power generation is quite different, FEderer and Nadal are the two best examples of the straight arm forehand. During practice, Nadal's is the easiest to see, so had you even posted the right player, you would've still lost terribly.